Electrical apparatus for obtaining filter pack density values

ABSTRACT

Electrical apparatus for obtaining density values for a filter pack for use with a production color film by comparing density values of a standard color film and its filter pack with the production color film, said apparatus having visual indicators for displaying the obtained net density values for the filter pack for the production color film. A computation circuit is electrically connected to the visual indicators and to a standard color film circuit and to a pack control circuit and to a production color film circuit for electrically processing signals from a plurality of potentiometers in the respective circuits. The signals correspond to density values associated with the respective item recorded therein whereby when the computation circuit is activated, numerical density values for the filter pack for the production color film are displayed by the visual indicators.

United States Patent [72] Inventors John V. Hanline Kansas City, Mo.;Daniel M. Chopin, Shawnee Mission, Thus. [21] Appl. No. 801,350 [22]Filed Feb. 24, 1969 [45] Patented Dec. 28, 1971 [73] Assignee FilmEquipment Manufacturing Co. Kansas City, Mo.

[54] ELECTRICAL APPARATUS FOR OBTAINING FILTER PACK DENSITY VALUES 4Claims, 3 Drawing Figs.

[52] U.S. Cl 235/193, 235/184, 356/177 [51 Int. Cl G06g 7/48, G0 1 j3/46 [50] Field 01 Search 235/193, 184, 185; 356/177, 173

[56] References Cited UNITED STATES PATENTS 3,018,050 1/1962 Barrell235/193 RE FEHENCE SOURCE COMPUTATION 3,270,190 8/1966 Lambert 235/184 X3,329,808 7/1967 Fisher 235/193 3,406,281 10/1968 Buchanan et a1.235/193 Primary Examiner-Joseph F. Ruggiero Attorney- Fishbum, Gold andLitman ABSTRACT: Electrical apparatus for obtaining density values for afilter pack for use with a production color film by comparing densityvalues of a standard color film and its filter pack with the productioncolor film, said apparatus having visual indicators for displaying theobtained net density values for the filter pack for the production colorfilm. A computation circuit is electrically connected to the visualindicators and to a standard color film circuit and to a pack controlcircuit and to a production color film circuit for electricallyprocessing signals from a plurality of potentiometers in the respectivecircuits. The signals correspond to density values associated with therespective item recorded therein whereby when the computation circuit isactivated, numerical density values for the filter pack for theproduction color film are displayed by the visual indicators.

POWER SOURCE.

PATENTED UEB28 am SHEET 1 or 2 INVENTORS. JOHN V. HANUNE n DAN\EL M.CHAPIN zal-lm gr o m ATTORNEYS ELECTRICAL APPARATUS FOR OBTAINING FILTERPACK DENSITY VALUES The present invention relates to photographicapparatus and more particularly to electrical apparatus for comparingdensity values of a standard color film and its filter pack with densityvalues of a production color film to obtain density values for a filterpack for use with the production color film.

The principal objects of the present invention are: to provide anelectrical apparatus for simultaneously determining and visuallydisplaying net density values for a subtractive filter pack for use witha production color film; to provide such an electrical apparatus adaptedto compare respective density values of a standard color film and afilter pack associated therewith with density values of a productioncolor film to obtain density values for a filter pack for use with theproduction color film; to provide such an electrical apparatus adaptedto provide results equal to solution of the equation D,-D ,,+P,I*J.D.=Pwherein D and D are red and green and blue density values of thestandard color film and the production color film respectively and P andP are the green and blue density values of a filter pack for use withthe standard color film and the production color film respectively andND. is neutral density; and to provide such an electrical apparatuswhich is economical to manufacture, easily maintained, positive anddirect in operation, and particularly well suited for the proposed use.

Other objects and advantages of this invention will become apparent fromthe following description taken in connection with the accompanyingdrawings wherein are set forth by way of illustration and examplecertain embodiments of this invention.

F IG. 1 is a perspective view of a cabinet containing an electricalapparatus for obtaining density values for a production filter packembodying features of the present invention.

F IG. 2 is a wiring diagram of the electrical apparatus for obtainingthe filter pack density values with the essential operating partsdiagrammatically shown.

FIG. 3 is a detailed wiring diagram of a computation circuit for theelectrical apparatus.

Referring more in detail to the drawings:

The reference numeral 1 generally designates a cabinet for containingelectrical apparatus 2 for obtaining density values for a filter pack(not shown) for use with a production color film (not shown). Theelectrical apparatus 2 has a plurality of adjustable potentiometers,each adapted to produce a signal having a coded value responsive toadjustment thereof and a computation circuit 3 electrically connected tothe potentiometers for processing the signals therefrom. The electricalapparatus 2 has visual indicators 4 and 5 electrically connected to thecomputation circuit 3 for displaying numerical values corresponding toresults of processing the potentiometer signals with the numericalvalues displayed corresponding to density values of the filter pack forthe production color film. A computation reference source 6 iselectrically connected to the potentiometers and is adapted to produce areference signal of substantially constant intensity for generatingprecise potentiometer signals.

Potentiometers 7, 8 and 9 are arranged in a standard color film circuit10. The potentiometers 7, 8 and 9 are adjusted by knobs ll, 12 and 13respectively, each of which has dials 14 for visually displayingnumerical values corresponding to the adjustment of the respectivepotentiometers. In the illustrated electrical apparatus, the dials 14 onthe knobs ll, 12 and 13 display numerical values representing red, greenand blue density values respectively of a standard color film or controlfilm (not shown).

The potentiometers 7, 8 and 9 are mounted in series between conductorsl5 and 16 which are electrically connected to the computation referencesource 6 whereby, when the electrical apparatus 2 is activated by apushbutton 17, the potentiometers 7, 8 and 9 will produce signals whichcorrespond to the density values of red, green and blue respectively.

Potentiometers l8 and 19 are arranged in a pack control circuit 20 withthe potentiometers l8 and 19 being adjusted by knobs 21 and 22, each ofwhich have dials 23 for visually displaying green and blue net densityvalues ofa filter pack (not shown) for the standard color film orcontrol film. In the illustrated electrical apparatus 2, thepotentiometers l8 and 19 are connected in series between conductors 24and 25 which are also connected to the computation reference source 6for producing signals representing the green and blue net density valuesrespectively of the filter pack for use with the standard control film.

Potentiometers 26, 27 and 28 are arranged in a production color filmvcircuit 29 and are adjusted by knobs 30, 31 and 32 respectively, eachof which have dials 33 to visually display numerical values representingthe adjustment of the respective potentiometers. In the illustratedelectrical apparatus, the potentiometers 26, 27 and 28 are electricallyconnected in series between conductors 34 and 35 which are electricallyconnected to the computation reference source 6.

The computation circuit 3 is adapted to electrically sum positive andnegative signals from the red potentiometers 7 and 26 and from the greenpotentiometers 8, l8 and 27 and from the blue potentiometers 9, l9 and28 to produce net signals for processing in the computation circuit 3.

The computation circuit 3 includes a portion to receive the net signalassociated with the respective primary colors and has a red channel,green channel and blue channel respectively with a power source 36electrically connected to operational amplifiers 37, 38 and 39 in thered, green and blue channels respectively. A conductor 40 extendsbetween a neutral conductor 41 of the power source 36 and theoperational amplifiers 37, 38 and 39 with resistors 42, 43 and 44 beingelectrically connected between conductor 40 and noninverting inputs ofthe operational amplifiers 37, 38 and 39 respectively. The resistors 42,43 and 44 are each in the nature of 30 K0, Aw, or) 5 percent resistors.

Offset balancing potentiometers 45, 46 and 47 are associated with theoperational amplifiers 37, 38 and 39 respectively with thepotentiometers 45, 46 and 47 each being in the nature of 2.5 K!) ohmpotentiometers and being connected to the power source 36 by conductors48 and 49.

Amplification completion loops 50, 51 and 52 are associated with thered, green and blue channel operational amplifiers 37 38 and 39respectively with capacitors 53, 54 and 55 being positioned in theamplification completion loops 50, 51 and 52 respectively to average theinput to substantially reduce noise in the computation circuit 3.Resistors 56, 57 and 58 are connected across the amplificationcompletion loops 50, 51 and 52 respectively with each of the resistors56, 57 and 58 being in the nature of 200 KO, or 0.02 percent resistors.

A plurality of resistors 59 are connected to each of the respectiveoperational amplification completion loops 50, 51 and 52 and are also inthe nature of 200 K0, or 0.02 percent resistors.

The amplification completion loops 50, 5] and 52 are connected to outputconductors 60, 61 and 62 respectively whereby voltage in the outputconductor 60 corresponds to the integral red density (neutral density)of the filter pack for the production color film and the voltage in theoutput condoctors 61 and 62 corresponds to the integral net densitiesfor the green and blue channels respectively. The red or neutral densityis cancelled by the computation circuit 3 by electrically adding to thegreen and blue signals an electrical signal equivalent to but ofopposite sign to the red or neutral density thereby eliminating red orneutral density.

A switch 63 is positioned on a cabinet front panel 64 and is movablebetween an on" and an off" position to supply electrical power to thecomputation reference source 6 and the power source 36. The computationreference source 6 is adapted to produce a substantially constant outputreference signal, such as in the nature of l0.00 volts. Manipulation oradjustment of the various knobs varies respective resistances in therespective potentiometers whereby, when the reference signal passesthrough the respective potentiometers, a signal is produced having avalue responsive to adjustment thereof with the potentiometer signalscorresponding to respective density values. The potentiometer signalsare electrically summed for each of the red, green and blue channels incomputation circuit 3.

It is desirable to have the electrical apparatus 2 self-calibrating,therefore, a calibration circuit 65 is electrically connected to thecomputation circuit 3 and to the visual indicators 4 and 5.

The electrical apparatus 2 is adapted to provide results equivalent tothose obtainable by solving the equation D D +P,l-1.D.=P wherein D isred, green and blue density values of the standard color film or controlfilm and D is the red, green and blue density values of the productionfilm. P is the green and blue density values of a filter pack for usewith the control film and ND. is neutral density and it is preferablythe lesser density value of the red, green and blue density values andin the illustrated electrical apparatus, red has been selected as theneutral density to accommodate other printing operations. P is thedesired density values for a filter pack for use with the productioncolor film and P, is the density values displayed on the visualindicators 4 and 5 respectively.

A color print is made from the standard color film or the control filmand the density values of the standard color film and the filter packused therewith for making the color print are obtained by using adensitometer. The density values for the standard color film and itsfilter pack are placed in the electrical apparatus 2 by adjusting thepotentiometers 7, 8 and 9 and the potentiometers l8 and 19 whereby thedials l4 display values corresponding to the red, green and blue densityvalues of the standard color film on the knobs l1, l2 and 13respectively and the dials 23 display the density values of the filterpack on the knobs 21 and 22 respectively. A production color film fromwhich it is desired to make a color print having color characteristicscorresponding to the color print made from the standard color film andits filter pack is placed in a densitometer to obtain the red, green andblue density values thereof which are then placed in the electricalapparatus 2 by adjustment of the potentiometers 26, 27 and 28respectively. The pushbutton 17 is depressed to activate the computationcircuit 3 which processes the signals from the respective potentiometersin the circuits 10, 20 and 29 to visually display numerical values onthe visual indicators 4 and 5 corresponding to density values for afilter pack for use with the production color film having the densityvalues corresponding to the signals produced by the potentiometers 26,27 and 28.

It is to be understood that while we have illustrated and described oneform of our invention, it is not to be limited to the specific form orarrangement of parts herein described and shown.

What we claim and desire to secure by Letters Patent is:

1. Electrical apparatus for obtaining density values for a productionfilter pack for use in making a print from a production color film, theelectrical apparatus comprising:

a. a plurality of adjustable potentiometers each operative to produce asignal having a value responsive to adjustment thereof;

b. a plurality of circuits each having a plurality of saidpotentiometers therein arranged in a plurality of channels; saidpotentiometers being arranged in a color film density circuit and a packcontrol circuit and a production color film density circuit, saidpotentiometers in said color film density circuit being operative toproduce signals representing selected density values of a control colorfilm, said potentiometers in said pack control circuit being operativeto produce signals representing selected density values of a filter packfor use with the control color film in making a print therefrom, saidselected densit values of a production color film, said density valuesemg for the primary colors of red and green and blue for said color filmdensity circuit and said production color film density circuit, saiddensity values being for the primary colors of green and blue for saidpack control circuit and for the filter pack for the production colorfilm;

c. a computation circuit electrically connected to said potentiometersin said channels of said circuits for processing said signals therefrom,said computation circuit being operative to electrically sum saidpotentiometer signals for each of the respective colors and electricallycancel one of the respective colors from said electrical summation, saidcomputation circuit including an operational amplifier for the channelfor each of said primary colors and balancing means electricallyconnected to each of said operational amplifiers for balancing currenttherethrough and circuit noise reduction means electrically connected toeach of said operational amplifiers and a plurality of resistorselectrically connected to each of said operational amplifiers;

d. electric power means electrically connected to said computationcircuit for activating same;

e. a plurality of visual indicators electrically connected to saidcomputation circuit for displaying numerical values representing resultsof processing the potentiometer signals, said numerical 'valuesrepresenting density values for a filter pack for use in making a printfrom a production color film; and

f. a computation reference source operative to produce a referencesignal of substantially constant intensity for comparing eachpotentiometer signal therewith.

2. An electrical apparatus as set forth in claim 1 wherein:

a. said potentiometers are each digitally coded switches to correspondto said respective density values; and

b. said computation circuit processes said digitally coded signals in adigital manner.

3. An electrical apparatus as set forth in claim 2 including displaymeans operatively connected to each of said digitally coded switches fordisplaying numerical values representing adjustment of said respectivedigitally coded switches, said numerical values representing respectivedensity values of the standard color film and the filter pack thereforand the production color film.

4. An electrical apparatus for obtaining numerical density values for aproduction filter pack for use in making a print from a production colorfilm, the electrical apparatus comprising:

a. a plurality of adjustable potentiometers each operative to produce asignal having a value responsive to adjustment thereof;

b. a plurality of circuits each having a plurality of saidpotentiometers therein arranged in a plurality of channels;

c. a computation circuit electrically connected to each of saidpotentiometers in each of said channels of each of said circuits forprocessing said signals therefrom;

d. electric power means electrically connected to said computationcircuit for activating same;

e. a plurality of visual indicators electrically connected to saidcomputation circuit for displaying numerical values representing resultsof processing the potentiometer signals, said numerical valuesrepresenting density values for a filter pack for use in making a printfrom a production color film; and

f. a calibration circuit electrically connected to said computationcircuit and to each of said visual indicators whereby the electricalapparatus is self-calibrating.

1. Electrical apparatus for obtaining density values for a productionfilter pack for use in making a print from a production color film, theelectrical apparatus comprising: a. a plurality of adjustablepotentiometers each operative to produce a signal having a valueresponsive to adjustment thereof; b. a plurality of circuits each havinga plurality of said potentiometers therein arranged in a plurality ofchannels; said potentiometers being arranged in a color film densitycircuit and a pack control circuit and a production color film densitycircuit, said potentiometers in said color film density circuit beingoperative to produce signals representing selected density values of acontrol color film, said potentiometers in said pack control circuitbeing operative to produce signals representing selected density valuesof a filter pack for use with the control color film in making a printtherefrom, said potentiometers in said production color film densitycircuit being operative to produce signals representing selected densityvalues of a production color film, said density values being for theprimary colors of red and green and blue for said color film densitycircuit and said production color film density circuit, said densityvalues being for the primary colors of green and blue for said packcontrol circuit and for the filter pack for the production color film;c. a computation circuit electrically connected to said potentiometersin said channels of said circuits for processing said signals therefrom,said computation circuit being operative to electrically sum saidpotentiometer signals for each of the respective colors and electricallycancel one of the respective colors from said electrical summation, saidcomputation circuit including an operational amplifier for the channelfor each of said primary colors and balancing means electricallyconnected to each of said operational amplifiers for balancing currenttherethrough and circuit noise reduction means electrically connected toeach of said operational amplifiers and a plurality of resistorselectrically connected to each of said operational amplifiers; d.electric power means electrically connected to said computation circuitfor activating same; e. a plurality of visual indicators electricallyconnected to said computation circuit for displaying numerical valuesrepresenting results of processing the potentiometer signals, saidnumerical values representing density values for a filter pack for usein making a print from a production color film; and f. a computationreference source operative to produce a reference signal ofsubstantially constant intensity for comparing each potentiometer signaltherewith.
 2. An electrical apparatus as set forth in claim 1 wherein:a. said potentiometers are each digitally coded switches to correspOndto said respective density values; and b. said computation circuitprocesses said digitally coded signals in a digital manner.
 3. Anelectrical apparatus as set forth in claim 2 including display meansoperatively connected to each of said digitally coded switches fordisplaying numerical values representing adjustment of said respectivedigitally coded switches, said numerical values representing respectivedensity values of the standard color film and the filter pack thereforand the production color film.
 4. An electrical apparatus for obtainingnumerical density values for a production filter pack for use in makinga print from a production color film, the electrical apparatuscomprising: a. a plurality of adjustable potentiometers each operativeto produce a signal having a value responsive to adjustment thereof; b.a plurality of circuits each having a plurality of said potentiometerstherein arranged in a plurality of channels; c. a computation circuitelectrically connected to each of said potentiometers in each of saidchannels of each of said circuits for processing said signals therefrom;d. electric power means electrically connected to said computationcircuit for activating same; e. a plurality of visual indicatorselectrically connected to said computation circuit for displayingnumerical values representing results of processing the potentiometersignals, said numerical values representing density values for a filterpack for use in making a print from a production color film; and f. acalibration circuit electrically connected to said computation circuitand to each of said visual indicators whereby the electrical apparatusis self-calibrating.